Hot-fill container having improved label support

ABSTRACT

A plastic container that is adapted for adjustment to internal volumetric changes such as those that occur during the hot-fill process includes a container body defining an internal space. The container body includes a main body portion having a plurality of vacuum panels disposed about an outer circumference thereof and a corresponding plurality of columns interposed between the vacuum panels. A label covers at least a portion of the vacuum panels and the columns. The label has a first portion having a first surface area that is in contact with the container and a second portion having a second surface area that is not in contact with the container. A ratio of said first surface area to said second surface area is at least 1.0, thereby ensuring superior label support. The main body portion further has a maximum outer radius and a maximum depth that is defined with respect to the maximum outer radius. A ratio of the maximum depth to the maximum outer radius is preferably no greater than about 0.2, which also contributes to the quality of the label support.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to the field of plastic containers, and more particularly to plastic containers that are designed to accommodate volumetric expansion and contraction such as that inherent to the hot-fill packaging process or to packaging applications where internal pressurization is anticipated.

2. Description of the Related Technology

Many products that were previously packaged using glass containers are now being supplied in plastic containers, such as containers that are fabricated from polyesters such as polyethylene terephthalate (PET).

PET containers are typically manufactured using the stretch blow molding process. This involves the use of a preform that is injection molded into a shape that facilitates distribution of the plastic material within the preform into the desired final shape of the container. The preform is first heated and then is longitudinally stretched and subsequently inflated within a mold cavity so that it assumes the desired final shape of the container. As the preform is inflated, it takes on the shape of the mold cavity. The polymer solidifies upon contacting the cooler surface of the mold, and the finished hollow container is subsequently ejected from the mold.

Hot fill containers are designed to be used with the conventional hot fill process in which a liquid or semi-solid product such as fruit juice, sauce, salsa, jelly or fruit salad is introduced into the container while warm or hot, as appropriate, for sanitary packaging of the product. After filling, such containers undergo significant volumetric shrinkage as a result of the cooling of the product within the sealed container. Hot fill type containers accordingly must be designed to have the capability of accommodating such shrinkage. Typically this has been done by incorporating one or more vacuum panels into the side wall of the container that are designed to flex inwardly as the volume of the product within the container decreases as a result of cooling. Several vacuum panels are typically provided, with integral column structures interposed between the respective vacuum panels. The vacuum panel regions of conventional hot fill containers are usually recessed with respect to the adjacent columns.

In many cases, the needs of a manufacturer require that an adhesive or shrink-fit label be secured to the container over the vacuum panels. In order to avoid excessive crinkling or deformation of the label when the container is squeezed or when volumetric expansion or contraction occurs within the container, it is important that the vacuum panels and the container as a whole be designed to provide as much support for the label as possible. In some cases, one or more raised areas are provided within the vacuum panel for improved label support. These are typically referred to as islands. However, even containers having vacuum panels with islands typically have a significant amount of surface area that is not in direct contact with the label. Air gaps accordingly exist between the container and the label. In one conventional container having six vacuum panels that is marketed by the assignee of this invention, the ratio of the surface area under the label that is in direct contact with the label to the surface area under the label that is not in direct contact with the label is about 0.85. This is typical for containers of this type.

In terms of design priorities, conventional measures that can be taken to improve label support often have the unwanted effect of reducing the efficacy of the vacuum panels at accommodating volumetric expansion and contraction. The design of such containers is also often influenced by the aesthetic preferences of manufacturers, which in some instances can place limitations of the size of the vacuum panels and on structure for providing label support.

A need exists for an improved vacuum panel configuration for a plastic container that achieves optimal label support, vacuum uptake capacity and aesthetics.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the invention to provide an improved vacuum panel configuration for a plastic container that achieves optimal label support, vacuum uptake capacity and aesthetics.

In order to achieve the above and other objects of the invention, a plastic container that is adapted for adjustment to internal volumetric changes includes a container body defining an internal space. The container body includes a main body portion having a plurality of vacuum panels disposed about an outer circumference thereof and a corresponding plurality of columns interposed between the vacuum panels. A label covers at least a portion of the vacuum panels and the columns. The label has a first portion having a first surface area that is in contact with the container and a second portion having a second surface area that is not in contact with the container. A ratio of the first surface area to the second surface area is at least 1.0.

A plastic container that is adapted for adjustment to internal volumetric changes according to a second aspect of the invention includes a container body defining an internal space. The container body has a main body portion having a plurality of vacuum panels disposed about an outer circumference thereof and a corresponding plurality of columns interposed between the vacuum panels. A label covers at least a portion of the vacuum panels and the columns. At least one of said columns comprises a raised transition portion that is integral with an adjacent vacuum panel. The raised transition portion extends radially outwardly with respect to an adjacent portion of the column, whereby the adjacent vacuum panel is elevated with respect to portions of the column in order to improve label support.

These and various other advantages and features of novelty that characterize the invention are pointed out with particularity in the claims annexed hereto and forming a part hereof. However, for a better understanding of the invention, its advantages, and the objects obtained by its use, reference should be made to the drawings which form a further part hereof, and to the accompanying descriptive matter, in which there is illustrated and described a preferred embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of a container that is constructed according to a preferred embodiment of the invention;

FIG. 2 is a cross-sectional view taken along lines 2-2 in FIG. 1;

FIG. 3 is a cross-sectional view taken along lines 3-3 in FIG. 1;

FIG. 4 is a diagrammatical depiction of a label secured to the container as it is shown in FIG. 2; and

FIG. 5 is a diagrammatical depiction of a label secured to the container as is shown in FIG. 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

Referring now to the drawings, wherein like reference numerals designate corresponding structure throughout the views, and referring in particular to FIG. 1, a plastic container 10 that is constructed according to a preferred embodiment of the invention is adapted for adjustment to internal volumetric changes, such as those that typically occur during the hot fill process or for applications in which internal pressurization of the container 10 is anticipated.

Container 10 is preferably fabricated from a material such as polyethylene terephthalate (PET) using a conventional reheat stretch blow molding process. It includes a bottom portion 12, a threaded upper finish portion 14, a dome or bell portion 16 and a main body portion 18. The main body portion 18 is preferably substantially cylindrical in shape and has a plurality of vacuum panels 20 disposed about an outer circumference of the main body portion 18. A corresponding plurality of columns 22 is provided, with each column 22 being interposed between two adjacent vacuum panels 20.

In the preferred embodiment, the vacuum panels 20 have an hourglass shape with relatively wide upper and lower portions and a relatively narrow central portion as viewed in side elevation, and the columns 22 have a complementary bow shape having a relatively wide central portion and relatively narrow upper and lower portions. The vacuum panels 20 and the columns 22 are preferably arranged in a repeating pattern that extends about the entire circumference of the main body portion 18.

The vacuum panels 20 are preferably configured so as to have no island or other raised portion defined therein. Accordingly, the entire surface area of each of the vacuum panels 20 is available for flexion in order to accommodate vacuum uptake during the hot fill process.

Each of the vacuum panels 20 is preferably slightly convex as viewed in transverse cross-section as shown in FIGS. 2 and 3, with a transverse radius of curvature that is preferably substantially constant longitudinally from the top of the vacuum panel 20 to the bottom of the vacuum panel 20.

As may be seen in FIGS. 2 and 3, the main body portion 18 as viewed in any horizontal cross-section includes a maximum outer radius R_(MAX). As viewed in horizontal cross-section, it will be seen that each of the columns 22 includes a central raised portion 26 that represents the maximum outer radius, a pair of raised transition portions 28 that are integral with an adjacent vacuum panel 20 and a pair of recessed portions 30 that are positioned between the central raised portion 26 and a raised transition portions 28. Each of the raised transition portions 28 extends radially outwardly with respect to an adjacent portion of the column 22, namely the recessed portion 30, so that the adjacent vacuum panel 20 is elevated with respect to portions of the column 22 in order to improve label support.

Accordingly, in the preferred embodiment each of the columns 22 has a W-shaped cross-section that provides enhanced label support. Additionally, the W-shaped cross sections of the columns 22 create an accordion effect permitting expansion of the main body portion 18 and additional vacuum uptake capacity together with the vacuum uptake capacity that is provided by the flexible vacuum panels 20.

Each of the vacuum panels 20 further has a maximum depth D_(VP) with respect to the maximum outer radius R_(MAX) of the main body portion 18 within the same horizontal cross-section. This represents the maximum depth of the main body portion 18. Preferably, the maximum depth of the main body portion 18 as expressed as a ratio with respect to the maximum outer radius R_(MAX) is no greater than about 0.2. More preferably, this ratio is no greater than about 0.1.

The recessed portions 30 of the columns 22 have a maximum depth D_(R), and the raised transition portions 28 have a minimum depth D_(OT). Preferably, the ratio of D_(R) to D_(OT) is within a range of about 1 to about 2. The vacuum panels 20 have a length L_(VP) and the columns 22 have a length L_(C) as viewed in horizontal cross-section.

Referring briefly to FIGS. 4 and 5, it will be seen that container 10 further includes a label 24 that covers at least a portion of both the vacuum panels 20 and the columns 22. Label 24 preferably extends about an entire circumference of the main body portion 18. In the preferred embodiment, label 24 covers substantially all of the surface area of the vacuum panels 20 and the columns 22.

Label 24 has a first portion having a first surface area that is in contact with the container 10, and more specifically the main body portion 18, and a second portion having a second surface area that is not in direct contact with the main body portion 18. As may be seen in FIG. 5, which is a representation of how the label 24 fits the main body portion 18 of the container 10 as viewed in cross-section along lines 3-3 in FIG. 1, the label 24 is in direct contact with the main body portion 18 in areas C_(VP) over the vacuum panels 20 and in areas C_(C) over a central raised portion 26 of each of the columns 22. The label 24 is not in direct contact with the main body portion 18 in areas N_(R) that overlay portions of the raised transition portions 28 and the intermediate recessed portions 30 of the columns 22. Accordingly, a very high percentage of the label 24 is in direct contact with the main body portion 18, with only a small air gap between the label 24 and the main body portion 18 existing over the outermost portions of the columns 22.

Preferably, the ratio of the first surface area to the second surface area is at least 1.0. More preferably, the ratio of the first surface area to the second surface area is at least 1.3, and most preferably the ratio of the first surface area to the second surface area is at least 1.6.

The main body portion 18 of the container 10 accordingly undergoes very little depth change when squeezed, which minimizes crinkling and the potential for initiation of delamination of the label 24.

It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. 

1. A plastic container that is adapted for adjustment to internal volumetric changes, comprising: a container body defining an internal space, said container body comprising a main body portion having a plurality of vacuum panels disposed about an outer circumference thereof and a corresponding plurality of columns interposed between the vacuum panels; and a label covering at least a portion of said vacuum panels and said columns, said label having a first portion having a first surface area that is in contact with said container and a second portion having a second surface area that is not in contact with said container, and wherein a ratio of said first surface area to said second surface area is at least 1.0.
 2. A plastic container according to claim 1, wherein said ratio of said first surface area to said second surface area is at least 1.3.
 3. A plastic container according to claim 1, wherein said ratio of said first surface area to said second surface area is at least 1.6.
 4. A plastic container according to claim 1, wherein said vacuum panels and said columns are arranged in a repeating pattern that extends about an entire circumference of said main body portion.
 5. A plastic container according to claim 1, wherein said vacuum panels are configured so as to have no island defined therein.
 6. A plastic container according to claim 1, wherein said label extends about an entire circumference of said main body portion.
 7. A plastic container according to claim 1, wherein at least one of said columns comprises a raised transition portion that is integral with an adjacent vacuum panel, said raised transition portion extending radially outwardly with respect to an adjacent portion of said column, whereby the adjacent vacuum panel is elevated with respect to portions of said column in order to improve label support.
 8. A plastic container according to claim 7, wherein said at least one of said columns includes two of said raised transition portions, each of said raised transition portions being integral with a respective adjacent vacuum panel, a raised central portion that is positioned between said raised transition portions and two recessed portions, each of said recessed portions being positioned between said raised central portion and a respective one of said raised transition portions.
 9. A plastic container according to claim 1, wherein said main body portion has a maximum outer radius, and wherein said main body portion has a maximum depth with respect to said maximum outer radius, with a ratio of said maximum depth to said maximum outer radius being no greater than about 0.2.
 10. A plastic container according to claim 9, wherein said ratio of said maximum depth to said maximum outer radius being no greater than about 0.1.
 11. A plastic container that is adapted for adjustment to internal volumetric changes, comprising: a container body defining an internal space, said container body comprising a main body portion having a plurality of vacuum panels disposed about an outer circumference thereof and a corresponding plurality of columns interposed between the vacuum panels; a label covering at least a portion of said vacuum panels and said columns; and wherein at least one of said columns comprises a raised transition portion that is integral with an adjacent vacuum panel, said raised transition portion extending radially outwardly with respect to an adjacent portion of said column, whereby the adjacent vacuum panel is elevated with respect to portions of said column in order to improve label support.
 12. A plastic container according to claim 11, wherein said at least one of said columns includes two of said raised transition portions, each of said raised transition portions being integral with a respective adjacent vacuum panel, a raised central portion that is positioned between said raised transition portions and two recessed portions, each of said recessed portions being positioned between said raised central portion and a respective one of said raised transition portions.
 13. A plastic container according to claim 11, wherein said main body portion has a maximum outer radius, and wherein said main body portion has a maximum depth with respect to said maximum outer radius, with a ratio of said maximum depth to said maximum outer radius being no greater than about 0.2.
 14. A plastic container according to claim 13, wherein said ratio of said maximum depth to said maximum outer radius being no greater than about 0.1.
 15. A plastic container according to claim 11, wherein said vacuum panels and said columns are arranged in a repeating pattern that extends about an entire circumference of said main body portion.
 16. A plastic container according to claim 11, wherein said vacuum panels are configured so as to have no island defined therein.
 17. A plastic container according to claim 11, wherein said label extends about an entire circumference of said main body portion. 